Authors

Kejun Xie, Meng Wang, Yugeng Huang, Huijiao Liu#

Departments

Department of Ophthalmology, Second Yinzhou District Hospital, Ningbo, PR China

Abstract

Objective: To explore the effect and mechanism of Akt on diabetic retinal vascular endothelial cells. 

Methods: A total of 30 C57BL/6J rats (clean grade) were randomly divided into a normal control group (n = 10), model group (n = 10) and treatment group (n = 10). To establish diabetes mellitus (DM), the model group and the treatment group were induced by intravenous injection of streptozotocin into the tail vein. At the first and third week after induction, Akt inhibitor was injected under microscope into the vitreous cavity of the treatment group, and 0.9% aseptic saline of the same volume was injected into the vitreous cavity of the left eye of the model group. The number of vascular endothelial cells breaking through the retinal inner limiting membrane was assessed under an optical microscope. Apoptosis of retinal vascular endothelial cells in diabetic rats was detected by TUNEL staining. The expression of pAkt and VEGF protein in rat retinal tissue was detected by immunohistochemistry. The expression of pAkt and VEGF mRNA in rat retinal tissue was detected by RT-PCR assay.

Results: The number of vascular endothelial cell nuclei breaking through the inner retinal membrane in the model group was significantly higher than that in the treatment group, and there was a significant difference in the average number of vascular endothelial cell nuclei per section between the two groups (P<0.05). There was no apoptosis in the retinal vascular endothelial cells of the normal rats. The number of cells undergoing apoptosis in the retinal vascular endothelial cells in the model group was distinctively higher than that in the treatment group and the normal control group, and the difference was statistically significant (P<0.05). The expression of pAkt and VEGF protein in the retinal tissue of the model group was strongly positive in new blood vessels of the ganglion cell layer, the inner nuclear layer and the outer plexiform layer. The expression of pAkt and VEGF protein in the retinal tissue of the treatment group was markedly lower in new blood vessels of the ganglion cell layer, the inner nuclear layer and the outer plexiform layer, and there was a significant difference between the two groups (P<0.05). The expression of pAkt and VEGF mRNA in retinal tissue of the model group was high. Moreover, the expression of pAkt and VEGF mRNA in retinal tissue of the treatment group was remarkably lower than that of the model group, and there was a significant difference between the two groups (P<0.05).

Conclusion: Akt inhibitor can significantly reduce apoptosis of diabetic retinal vascular endothelial cells, and its mechanism of action may be related to the fact that Akt inhibitor can down-regulate retinal VEGF expression by blocking the Akt-signaling pathway.

Keywords

Akt inhibitor, diabetic retinopathy, vascular endothelial cell, action mechanism.

DOI:

10.19193/0393-6384_2020_3_273